\section{Exact arithmetic checks}\label{app:checks} \subsection{Logarithm bounds and endpoint comparisons} \label{app:endpoint-checks} Here is the finite rational calculation used in Section~\ref{sec:count}. For a rational $x\ge1$, write $x=2^j y$ with $j\ge0$ and $1\le y<2$, and put $z=(y-1)/(y+1)$. With $M=18$, define \[ L_M(y)=2\sum_{h=0}^{M-1}\frac{z^{2h+1}}{2h+1},\qquad R_M(y)=\frac{2z^{2M+1}}{(2M+1)(1-z^2)}. \] The positive series $\log y=2\operatorname{atanh}z$ gives \[ L_M(y)\le\log y\le L_M(y)+R_M(y). \] Applying the same formula to $2$ gives bounds for $\log2$. Adding $j$ times those bounds gives rational numbers $\underline{\log}(x)$ and $\overline{\log}(x)$ enclosing $\log x$. The remainder follows by replacing all denominators in the tail by $2M+1$ and summing the resulting geometric series. The checker computes $\varphi(d)$ by counting coprime integers and then forms $D_k$. For each closed endpoint $s_k$, it computes \[ 2\left\lceil D_k\left(33+\frac{45}{2} \underline{\log}(k)\right)\right\rceil, \qquad 2\left\lceil D_k\left(33+\frac{45}{2} \overline{\log}(k)\right)\right\rceil. \] These integers agree in every required case, thereby isolating the endpoint exactly. It then performs the following rational comparisons: \begin{center} \begin{tabular}{@{}lrr@{}} \toprule Comparison&Number of cases&Index of smallest margin\\ \midrule Unrounded, $26\le k\le255$&230&29\\ Rounded, $3\le k\le25$&23&3\\ \bottomrule \end{tabular} \end{center} After subtraction of $968/6615$, the margins are strictly greater than $24529/10^8$ and $14325/10^8$, respectively, as used in the proof. All calculations use integer or rational arithmetic. The checker also verifies the constants in \eqref{eq:tail-T}--\eqref{eq:tail-G}, the two small floors at $s=160,364$, and the positive coefficient bound at the end of Section~\ref{sec:count}. The elementary bounds on $\pi$ can be verified independently of decimal approximations. For the upper bound, \[ 0<\int_0^1\frac{x^4(1-x)^4}{1+x^2}\,dx=\frac{22}{7}-\pi. \] For the lower bound $\pi>157/50$, the checker uses Machin's identity $\pi=16\arctan(1/5)-4\arctan(1/239)$ with eight terms of the alternating arctangent series and its next-term error bound. \subsection{Checks of the construction identities} The positive-definiteness proof in Section~\ref{sec:gram} works for every $B$. We also check its normalization and the arithmetic identities by separate finite calculations. At each of the ten parameter choices in Section~\ref{sec:endpoints}, two partial-fraction algorithms over the field with $1\,000\,003$ elements agree with an exact rational calculation of the Gram matrix. The rational calculation uses explicit moments. Every element of $\mathcal A$ occurs in $\Lambda$, because the kernel poles are numerator zeros. With all fractions reduced, put \[ \Delta=\prod_{\alpha=v/d\in\Lambda}d^2,\qquad V(x)=\prod_{\alpha=v/d\in\Lambda\setminus\mathcal A}(d^2x+v^2). \] Then $\prod_{\alpha\in\Lambda}(x+\alpha^2)/Q(x)=V(x)/\Delta$. For $0\le k